DE2822409A1 - METHOD OF MANUFACTURING PLASTIC BOWLS - Google Patents

Description

Patent application
Method of making plastic trays

The invention relates to a method for producing plastic trays, especially of hollow plastic bodies.

It is known for the production of hollow plastic bodies from cores
To use metal alloys; however, these cores are made massive, which requires a large amount of metal. The energy costs in manufacturing such cores are also high.

It is the object of the invention to propose a method that the
Material consumption in the production of plastic hollow bodies is reduced and the energy used is also reduced.

This goal is achieved by the method steps specified in the claims achieved.

The devices used in the method according to the invention are shown in the figures.

809850 / 07Ö2

Company headquarters: Cologne · Registergdricht Köln, HRB 84 ■ Chairman of the supervisory board: Hans Schaberger

Board of Directors: Peter Weiher. Chairman - Horst Bergemann ■ Waldemar Ebers ■ Wilhelm Inden ■ Alfred Langer
Deputy: Hermann Dederichs · Hans Wilhelm Gab · Paul A. Guckel · Hans-Joachim Lehmann · Dieter Ullsperger

Ford / GB-179 / May 19, 1978

Show it:

1 shows a schematic representation of a device for carrying out the method according to the invention;

FIG. 2 shows a side view of an object as it can be manufactured as a result of the method according to the invention; FIG.

3 shows a schematic representation of the main units of the method according to the invention.

As can be seen from the figures, contains an insulated and heated Container 10 the liquid metal alloy. A burner 12 is arranged under the container, which keeps the metal alloy at a temperature level holds around the melting point. The liquid metal is fed from the container 10 to a low-pressure casting mold 13.

As can be seen in particular from FIG. 3, the low-pressure casting mold contains 13 a jacketed and heated pipe 30 which has a two-piece shape 32. The pipeline 30 can pass through a heating element 31 are heated; the pipeline 30 is in communication with the container 10 via a feed line 33.

The container 10 is hermetically sealed and via the feed line 33 is connected to the low-pressure casting mold 13. On the container 10 there is also a connection for a gas line 35. Through this line inert gas is pumped into the container 10 so that the liquid material rises into the low-pressure casting mold 13. The mold 32 contains coolant directions, such as a cooling jacket 16 through which the temperature of the mold can be controlled. At the beginning of the production the tubing 30 is heated to prevent the alloy from breaking immediately

becomes solid. 809850/0702

Fcrd / GB-179 / May 19, 1978

By introducing the gas into the container 10 through the gas line 35 the alloy rises into mold 32. The air displaced thereby escapes through an outlet 38. Is the mold with molten material is filled, the supply of metal alloy is stopped. The material on the wall of the mold 32 then becomes solid and after being reduced Due to the pressure in the gas line 35, the material that has not set flows from the mold 32 back into the container 10. It is also possible, in another form of the method, to force the molten material of the alloy into the mold 32 through a piston; by pulling back the piston, the material that has not become solid then returns to the container 10.

The mold 32 is then opened and the metal shell can be removed from the Shape to be removed. These cores, as the metal hollow forms are now referred to, pass through a transport device 18 can, in the area 20.

In the area 20 are several compression molds for the production of Plastic material set up ^ as the manufacturing process for the plastic material bodies is more time-consuming than the production of the cores from metal itself, several facilities are provided here. Any molding press 22 is of conventional construction. Using the cores made of the metal alloy used, the plastic trays or Plastic hollow body made.

Then the plastic trays with the cores in them heated after the plastic material has hardened. A temperature is used that is sufficient for the material of the core to melt, but not to affect the structure of the plastic material. This heating can take place in the pipeline 30; the resulting molten material then flows through a line to the Container 10 closed. 809850/0702

e e r s e i f e

Claims (6)

Claims 1. Process for the production of plastic trays, in particular of Plastic hollow bodies, consisting of the following process steps: a) a core is made from a metal alloy, the metal alloy used having a melting point, which is higher than the curing temperature of the plastic trays, but which is lower than the temperature at which the Plastic shell disintegrates after hardening; b) the material for the plastic shells is molded around the core and then cured; c) Core and plastic shells are heated to a temperature sufficient to melt the core, leaving the melted The metal alloy material remains inside the plastic trays. 2. The method according to claim 1, characterized in that for the production of the core, a metal alloy in a low-pressure casting mold (13) is introduced and there is solid in the outer areas, the not solidified material of the Metal alloy is withdrawn from the low-pressure casting mold (13) after the outer areas have solidified. 3. The method according to claim 1 and 2, characterized in that a tin-bismuth alloy is used as the metal alloy will. 4. The method according to claim 1 to 3, characterized in that that the plastic trays are made of polyester. 809850/0702 ORIGINAL iNSPECTie -Z- Fcrd / GB-179 / May 19, 1978 5. The method according to claim 3, characterized in that g e k e η η ζ e i c hne t that the alloy of tin and bismuth is put together so that the melting point of the alloy is between 413 and 443 K. 6. The method according to claim 1 to 5, characterized in that that the material of the metal alloy after withdrawal from the casting mold the process within a temperature range of Melting point + 25 C is fed back. 809850/0702